Add support for @interfaceObject directive

.formatter.exs

@@ -1,6 +1,6 @@
 # Used by "mix format"
 [
-  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test,federation_compatibility}/**/*.{ex,exs}"],
   line_length: 120,
   import_deps: [:absinthe]
 ]

.gitignore

@@ -22,8 +22,25 @@ erl_crash.dump
 # Ignore package tarball (built via "mix hex.build").
 absinthe_federation-*.tar
 
+# Federation test artifacts
+supergraph-compose.yaml
+supergraph-config.yaml
+supergraph.graphql
+results.md
+
+# Local temporary Dockerfiles
+federation_compatibility_dockerfile.local
+
+# Local text editor files
 .vscode
+
+# Local version config
+.mise.toml
 .tool-versions*
+
+# Local OS-specific files
 .DS_Store
+
+# PLT files
 /priv/plts/*.plt
 /priv/plts/*.plt.hash

README.md

@@ -162,16 +162,19 @@ defmodule MyApp.MySchema do
 
 + extend schema do
 +   directive :link,
-+     url: "https://specs.apollo.dev/federation/v2.0",
++     url: "https://specs.apollo.dev/federation/v2.3",
 +     import: [
 +       "@key",
 +       "@shareable",
 +       "@provides",
++       "@requires",
 +       "@external",
 +       "@tag",
 +       "@extends",
 +       "@override",
-+       "@inaccessible"
++       "@inaccessible",
++       "@composeDirective",
++       "@interfaceObject"
 +     ]
 + end
 

federation_compatibility/lib/products_web/schema.ex

@@ -40,7 +40,7 @@ defmodule ProductsWeb.Schema do
     directive :link, url: "https://divvypay.com/test/v2.4", import: ["@custom"]
 
     directive :link,
-      url: "https://specs.apollo.dev/federation/v2.1",
+      url: "https://specs.apollo.dev/federation/v2.3",
       import: [
         "@extends",
         "@external",
@@ -51,7 +51,8 @@ defmodule ProductsWeb.Schema do
         "@requires",
         "@shareable",
         "@tag",
-        "@composeDirective"
+        "@composeDirective",
+        "@interfaceObject"
       ]
   end
 
@@ -256,6 +257,23 @@ defmodule ProductsWeb.Schema do
     end
   end
 
+  @desc """
+  type Inventory @interfaceObject @key(fields: "id") {
+    id: ID! @external
+    deprecatedProducts: [DeprecatedProduct!]!
+  }
+  """
+  object :inventory do
+    key_fields("id")
+    interface_object()
+
+    field :id, non_null(:id), do: external()
+
+    field :deprecated_products, non_null(list_of(non_null(:deprecated_product))) do
+      resolve &resolve_deprecated_products_for_inventory/3
+    end
+  end
+
   defp resolve_product(_parent, %{id: id}, _ctx) do
     {:ok, Enum.find(products(), &(&1.id == id))}
   end
@@ -307,16 +325,8 @@ defmodule ProductsWeb.Schema do
     end
   end
 
-  defp resolve_deprecated_product_reference(
-         %{sku: "apollo-federation-v1", package: "@apollo/federation-v1"},
-         _ctx
-       ) do
-    {:ok,
-     %DeprecatedProduct{
-       sku: "apollo-federation-v1",
-       package: "@apollo/federation-v1",
-       reason: "Migrate to Federation V2"
-     }}
+  defp resolve_deprecated_product_reference(%{sku: sku}, _ctx) do
+    {:ok, Enum.find(deprecated_products(), &(&1.sku == sku))}
   end
 
   defp resolve_deprecated_product_reference(_args, _ctx) do
@@ -339,6 +349,10 @@ defmodule ProductsWeb.Schema do
     {:ok, nil}
   end
 
+  defp resolve_deprecated_products_for_inventory(%{__typename: "Inventory"} = _parent, _args, _ctx) do
+    {:ok, deprecated_products()}
+  end
+
   defp resolve_deprecated_product_created_by(_deprecated_product, _args, _ctx) do
     {:ok, List.first(users())}
   end
@@ -363,6 +377,15 @@ defmodule ProductsWeb.Schema do
       }
     ]
 
+  defp deprecated_products(),
+    do: [
+      %DeprecatedProduct{
+        sku: "apollo-federation-v1",
+        package: "@apollo/federation-v1",
+        reason: "Migrate to Federation V2"
+      }
+    ]
+
   defp product_research(),
     do: [
       %ProductResearch{

federation_compatibility_dockerfile

@@ -1,4 +1,7 @@
 FROM elixir:1.14.2-alpine AS build
+ADD https://truststore.pki.rds.amazonaws.com/global/global-bundle.pem /usr/local/share/ca-certificates/aws-rds.crt
+ADD https://mobile.zscaler.net/downloads/zscaler2048_sha256.crt /usr/local/share/ca-certificates/zscaler.crt
+RUN cat /usr/local/share/ca-certificates/*.crt >> /etc/ssl/certs/ca-certificates.crt
 
 WORKDIR /
 COPY . .
@@ -28,6 +31,11 @@ RUN mix do compile, release
 
 # prepare release image
 FROM alpine:3.16 AS app
+ADD https://truststore.pki.rds.amazonaws.com/global/global-bundle.pem /usr/local/share/ca-certificates/aws-rds.crt
+ADD https://mobile.zscaler.net/downloads/zscaler2048_sha256.crt /usr/local/share/ca-certificates/zscaler.crt
+RUN cat /usr/local/share/ca-certificates/*.crt >> /etc/ssl/certs/ca-certificates.crt
+
+RUN apk update
 RUN apk add --no-cache openssl libgcc libstdc++ ncurses-libs
 
 WORKDIR /app

lib/absinthe/federation/notation.ex

@@ -277,6 +277,52 @@ defmodule Absinthe.Federation.Notation do
     end
   end
 
+  @doc """
+  Adds the `@interfaceObject` directive to the field which indicates that the
+  object definition serves as an abstraction of another subgraph's entity
+  interface. This abstraction enables a subgraph to automatically contribute
+  fields to all entities that implement a particular entity interface.
+
+  During composition, the fields of every `@interfaceObject` are added both to
+  their corresponding interface definition and to all entity types that
+  implement that interface.
+
+  More information can be found on:
+  https://www.apollographql.com/docs/federation/federated-types/interfaces
+
+  ## Example
+
+      object :media do
+        key_fields("id")
+        interface_object()
+
+        field :id, non_null(:id), do: external()
+        field :reviews, non_null(list_of(non_null(:review)))
+      end
+
+      object :review do
+        field :score, non_null(:integer)
+      end
+
+
+  ## SDL Output
+
+      type Media @interfaceObject @key(fields: "id") {
+        id: ID! @external
+        reviews: [Review!]!
+      }
+
+      type Review {
+        score: Int!
+      }
+
+  """
+  defmacro interface_object() do
+    quote do
+      meta :interface_object, true
+    end
+  end
+
   @doc """
   The `@tag` directive indicates whether to include or exclude the field/type from your contract schema.
 
@@ -309,6 +355,9 @@ defmodule Absinthe.Federation.Notation do
   The `@link` directive links definitions from an external specification to this schema.
   Every Federation 2 subgraph uses the `@link` directive to import the other federation-specific directives.
 
+  **NOTE:** If you're using Absinthe v1.7.1 or later, instead of using this macro, it's preferred to use the
+  `extend schema` method you can find in the [README](README.md#federation-v2).
+
   ## Example
 
       link(url: "https://specs.apollo.dev/federation/v2.0", import: ["@key", "@tag", "@shareable"])

lib/absinthe/federation/schema/phase/add_federated_directives.ex

@@ -33,6 +33,7 @@ defmodule Absinthe.Federation.Schema.Phase.AddFederatedDirectives do
     |> maybe_add_shareable_directive(meta)
     |> maybe_add_override_directive(meta)
     |> maybe_add_inaccessible_directive(meta)
+    |> maybe_add_interface_object_directive(meta)
     |> maybe_add_tag_directive(meta)
   end
 
@@ -107,6 +108,14 @@ defmodule Absinthe.Federation.Schema.Phase.AddFederatedDirectives do
 
   defp maybe_add_inaccessible_directive(node, _meta), do: node
 
+  defp maybe_add_interface_object_directive(node, %{interface_object: true, absinthe_adapter: adapter}) do
+    directive = Directive.build("interface_object", adapter)
+
+    add_directive(node, directive)
+  end
+
+  defp maybe_add_interface_object_directive(node, _meta), do: node
+
   defp maybe_add_tag_directive(node, %{tag: name, absinthe_adapter: adapter}) do
     directive = Directive.build("tag", adapter, name: name)
 

lib/absinthe/federation/schema/prototype/federated_directives.ex

@@ -118,6 +118,15 @@ defmodule Absinthe.Federation.Schema.Prototype.FederatedDirectives do
         ]
       end
 
+      @desc """
+      Indicates that an object definition serves as an abstraction of another subgraph's entity interface.
+      This abstraction enables a subgraph to automatically contribute fields to all entities that implement
+      a particular entity interface.
+      """
+      directive :interface_object do
+        on [:object]
+      end
+
       @desc """
       The `@tag` directive indicates whether to include or exclude the field/type from your contract schema.
       """

test/absinthe/federation/notation_test.exs

@@ -162,5 +162,37 @@ defmodule Absinthe.Federation.NotationTest do
       assert sdl =~ ~s{directive @custom on SCHEMA}
       assert sdl =~ ~s{directive @other on OBJECT}
     end
+
+    test "schema with an interfaceObject is valid" do
+      defmodule InterfaceObjectSchema do
+        use Absinthe.Schema
+        use Absinthe.Federation.Schema
+
+        extend schema do
+          directive :link, url: "https://specs.apollo.dev/federation/v2.3", import: ["@interfaceObject", "@key"]
+        end
+
+        query do
+          field :hello, :media
+        end
+
+        object :media do
+          key_fields("id")
+          interface_object()
+
+          field :id, non_null(:id), do: external()
+          field :reviews, non_null(list_of(non_null(:review)))
+        end
+
+        object :review do
+          field :score, non_null(:integer)
+        end
+      end
+
+      sdl = Absinthe.Schema.to_sdl(InterfaceObjectSchema)
+
+      assert sdl =~ ~s{import: ["@interfaceObject", "@key"])}
+      assert sdl =~ ~s{type Media @interfaceObject @key(fields: "id")}
+    end
   end
 end